Effect Of Different Surface Treatment Methods On The Bonding Strength Of Aged Composite Resin

Purpose:Different mechanical treatment methods were used to roughen the surface of the old composite resin.Single Bond Universal adhesive was used to bond with or without silane coupling agent to evaluate the bonding strength of the old composite resin repair interface with fresh composite resin under different treatment methods.Method:1.Preparation of aged resin blocksA mold with an inner diameter of 4 mm×4 mm×8 mm was made with silicone rubber impression material,and a support block of 4 mm×4 mm×4 mm was made with self-setting plastic powder and placed on the bottom of the mold 35 composite resin blocks of 4 mm×4 mm×4 mm were made with Z350 resin above the mold and stored in 37℃distilled water for 2 months.2.Experimental groupingAccording to the aged composite resin surface treatment methods were divided into groups:A:control group(no treatment);B:carborundum bur polishing;C:carborundum bur polishing+silane coupling agent;D:alumina sandblasting;E:alumina sandblasting+silane coupling agent;F:carborundum bur polishing+alumina sandblasting;G:carborundum bur polishing+alumina sandblasting+silane coupling agent.After the above surface treatment,Single Bond Universal adhesive is used to bond with fresh composite resin.3.Micro tensile bonding strength testAfter the above repair,the composite resin specimen was fixed on a hard tissue slicer for cutting,and the size of the specimen was about 1mm×1mm×8mm.Under stereopicroscope,the obtained specimens were carefully screened,and the defects containing bubbles and cracks were removed,and 10 qualified specimens were selected from each group.The sample was fixed on the fixture matching with the universal testing machine withα-ethyl cyan-acrylate adhesive,and the fixture was connected with the universal material testing machine,and the maximum load(N)when the sample broke was recorded at 1.0mm per minute.The microtensile bonding strength is calculated by the following formula:Microtensile bonding strength(Mpa)=maximum load(N)/bonding area(mm~2).4.Fracture interface evaluationThe fracture patterns of samples were observed under stereomicroscope,and the frequency of each fracture pattern was recorded.The fracture modes of the experimental samples can be divided into:(1)bonding interface fracture;(2)cohesive fracture(failure in aged/fresh resin);(3)Mixed fracture(two or more fracture forms)5.Statistical analysisStatistical software SPSS20.0 was used to conduct statistical analysis on the micro tensile bonding strength of each group of composite resin specimens measured.Quantitative data were described by x±s,and the mean value and standard deviation were calculated.One-way-anova method was used to conduct One-Way analysis of variance for the values of micro-tensile bonding strength of different samples,and LSD(Post-Hoc Test)was used to compare the values of micro-tensile bonding strength of different groups.The test level wasα=0.05.Independent sample t-test was performed for groups with or without silane coupling agent after the same mechanical treatment,and P<0.05 was considered to be significant and statistically significant.Results:1.The microtensile bond strength of the control group and the mechanical treatment group:group B>group A,group D>group A,group F>group A,P<0.05,the difference was statistically significant.2.The microtensile bond strength of the new-old composite resin after different mechanical surface treatments:group D>group B,P>0.05,the difference was not statistically significant;F group>B group,F group>D group,P<0.05,the difference was statistically significant.3.The microtensile bond strength of silane coupling agent after different mechanical treatments:group C>group B,group E>group D,group G>group F,P<0.05,the difference was statistically significant.4.The type microscope observation showed that the failure mode of resin specimens in each group was mainly adhesive interface fracture after micro-tensile test.Conclusion:1.Under the experimental conditions,compared with the control group,different mechanical treatment methods can significantly improve the micro-tensile bonding strength between the new and old resins.The micro-tensile bonding strength of the carborundum grinding combined with alumina sandblasting group is higher than that of the carborundum grinding group and alumina sandblasting group,while there is no significant difference between the carborundum grinding group and alumina sandblasting group.2.Under the experimental conditions,the repairing bonding strength between the aged resin and the fresh resin can be significantly improved by using silane coupling agent on the surface of the aged composite resin after different mechanical treatments.The repair effect of silane coupling agent combined with universal adhesive is better.